OP I'm gunna talk directly to you here.
You keep stressing good looking, hot chick or guy down the street. As if that's the formula for popularity. It's not. You're the only one keeping yourself from hanging out with the people who you deem "cool." And that's probably the first reason why you're in the predicament you're in. You put them up on a pedestal. They're no better than you in any way, shape or form.
You need sociability. Popularity means having friends, which is only done through being social. I, myself, am not super popular. I suck at keeping in contact. I can talk to pretty well anybody in a setting where we're forced to be together (school, work, etc) but as soon as we're off doing our own thing, I don't think about anyone else but myself or the direct people involved in what I'm doing. Does that make me a bad friend? I don't think so. Some people might.
There was a party last night. I was invited. What did I do? I played Ragnarok Online with friends from PC. Wow, what a loser I am. Nobody at that party was cooler than me, and nobody at that party was less cool than me. We're all equals. I didn't go for several reasons: (a) Parties are not my scene. I'm not a straight edge, but I know that if I get drunk I do stupid ****. I prefer smoking pot, and I'm not at all sociable when I'm high. I sit and think. If there's music playing, no matter how garbage it is, all my attention will be going towards it. If I'm addressed, I might be able to carry a conversation for a minute or so before I completely space out.
Reputation seems to be a big deal. It's only as big of a deal as you let it be, and you seem to let it be a big deal. I'm gunna tell you straight up, those people you wish you were partying with, probably have a terrible reputation among themselves. If they're drinking underage, it's all about impressing their peers. They do stupid **** they regret. Your reputation, even if you think you're a loser, is probably pristine compared to some of theirs. And I'm gonna tell you straight up what they think of you: Oh look, it's Bloodex, he probably doesn't want to hang out with us. I couldn't invite him to the party because it'd be awkward, we never talk. It'd be cool if he came to a party, though.
I don't know what my reputation in high school was. I think it was probably somewhere along the lines of "a kid who plays in a band and makes movies." Not bad if you ask me. It wasn't "oh man he's the life of the party!" or "wow what a loser, how does he even have friends?" I had one group of friends, they were the losers of the grade. I was one of the nerds. Never invited to parties, not very social. At the time, I hated it! I wanted so badly to be invited to parties. I thought exactly the way you do now. But even if you were invited to those parties, you would hate going there. You would feel out of place, and all of these people would have all these stories and inside jokes that you don't get at all.
My advice to you: make the best out of what you've got, and don't label anything. If you want to party because you want to know what it's like to get drunk, get drunk! Learn! If you want to know what it's like to smoke pot, smoke it. Get high. It's fun as hell. Just don't get out of hand. People usually get out of hand because they hang out with other people who enable it. You sound like someone that could very well keep track of himself and moderate things.
And trust me. Things will get better. Coming out of high school is quite an experience. I won't spoil anything, but you'll be hella happy. Mark my words.